Sports boards are popular for a variety of recreational activities, such as snow sledding, body boarding, surfing, etc. Wham-O, Inc.'s BOOGIE BOARD® body boards have been used for years by children and adults for sport in ocean surf and to cool off, in an entertaining way, on warm summer days. Similarly, Wham-O, Inc.'s SNOWBOOGIE® sleds have been used for recreation on winter days. Typical sports boards use an expanded foam core, a foam skin laminated to the top and side surfaces, and a solid skin having a thin foam backing laminated along the bottom surface. An example of a typical sports board is shown in U.S. Pat. No. 4.850,913 to Szabad. The sports board in Szabad includes a polyethylene film laminated to a polyethylene foam sheet to form a composite film/sheet laminate that is then laminated onto a polyethylene core. The laminated solid skin improves durability and reduces drag as the sports board slides along the snow or through the water. One problem with laminating a solid skin to the bottom of the sports board is that for proper adhesion between the solid skin and the core a thin foam-backing layer must be laminated to the solid skin prior to laminating the skin to the core of the board. Only after the foam-backing layer has been applied can the solid skin be laminated to the bottom surface of the sports board. If a solid skin was laminated directly to the core, either the core would blister, or the skin would be too rough and lack toughness.
Another problem with typical sports boards is the stiffness requirements of the core of the board make it uncomfortably firm. Often relatively dense expanded polymer foam must be used as the core to create a sports board with the proper stiffness. Using a dense expanded foam results in an uncomfortably hard board for a user to kneel or lie on.
Yet another problem encountered in sports boards is that with a slick solid skin laminated to the bottom surface the boards are not easily steered. A sports board constructed of foam lacks hard sharp edges that can be used to carve turns in the snow or water.
It would be desirable to develop a sports board that is easy to manufacture, has the needed stiffness, while including a comfortable surface for riding, and has a structure that enables greater steering control. Greater comfort may be achieved through the use a multi-layer expanded foam core, where each layer had a different density. A top layer may have a softer density for comfort, while a lower layer may have a higher density providing needed stiffness.